Aberdyfi beach was given a Blue Flag for the first time in 2006

Keep Wales Tidy, which co-ordinates the campaign, said the wet summer and high river levels could have increased the amount of pollutants in the sea.

Criccieth and Aberdyfi in Gwynedd, Llangrannog and Aberporth in Ceredigion and Amroth in Pembrokeshire failed tests during the bathing season.

The five beaches will not be able to fly a Blue Flag from next year.

Keep Wales Tidy said 44 beaches and five marinas flew the flag during the summer.

Chief executive Tegryn Jones said tests were carried out regularly during the bathing season and beaches could lose their flag at any time.

On the whole the quality of beaches along the Welsh coast is high Tegryn Jones, Keep Wales Tidy

He added: "Twenty samples might be taken from each beach during the bathing season and if it fails a number of samples then the flag is removed.

"There may be local reasons why they have failed, but one of those might have been the very wet summer.

"There's a good chance high river levels have taken pollutants into the sea, but on the whole the quality of beaches along the Welsh coast is high."

Gethin James, Aberporth county councillor, said his community was being penalised for the wet summer.

"Water quality readings from the previous year should not affect us receiving a blue flag a year on," he added.

Last year, more beaches than ever in Wales received Blue Flag status, which is awarded in 32 countries across the world.

Beaches are judged against 26 different criteria, including standard of bathing water, litter management and sustainable environmental management.